Pneumatic feeding mechanism for machine tools



May 12 1931. F. E. PHILLIPS PNEUMATIC FEEDING MECHANISM'FOR MACHINETOOLS Filed June 15, 1926 ATTORNEYS Patented May 12, 1931 unite TTESPArnT OFFICE FREDERICK E. PHILTJIPS, 0F NEWPORT, KENTUCKY, ASSIGNOR' OFONE-FOURTH. TO

ALLEN & ALLEN, \A rims corarosrn or or CINCINNATI, onio r ALFRED IVE.ALLEN AND MARS'ION ALLEN,

PNEUMATIC FEEDING MECHANISM FOR MACHINE TOOLS Application filed June 15,

My invention relates broadly to the general class of machine tools, andto pneumatic mechanism for feeding either the tools'or the work. Theparticular embodiment disclosed in the ensuing application, relatestofeeding mechanism for high speed drills and the like.

It is the object of my invention in the combination with a high speeddrill, to provide means for feeding the rotatable tool carrying shaftpneumatically, and in combination with this pneumatic means to provide avalve mechanism for the supply of air for actuating the said means whichwill be positive in operation, and which may be readily con trolled by amanually movable member.

Referring to the drawingsin which I have, illustrated a preferredembodiment illustratingthe principle involved in the application of myinvention to a high speed drill:

Figure 1 is aside elevation with parts in section showing the pneumaticcylinderwith the connecting pipes to the valve mechanism. Figure 2 is avertical section of the valve control mechanism, with a preferred typeof control handle. I Generally indicated at 1 is the shaft of the drill,which' is rotated by suitable mechanism which is not shown, as it formsno part of this invention. Reference is made to the patent to Kirby,971,679, as an example of a simple type of mechanical means ofcontrolling the feed of a rotatable shaft carrying a drilling tool. Theshaft 1 is rotatable andalso movable longitudinally, so that the feedingmeans for the shaft is of necessity some movable member which appliesforce longitudinally without impairing the rotation of the shaft. Thetool holding end of the rotatable shaft is indicated at 2. I have showna cylinder having walls 3 and an upper head 4 and a lower head 5. Asleeve 6 is mounted on the shaft 1, and bearings 7 preferably of theball type, provide a freely rotatable connection between the shaft andthe piston hub 8, which extends through the top and bottom head. Thepiston head 9 has rings 10, or other suitable means of preventingleakage between the outer periphery of the head and the cylinder walls,and packing glands 11 are provided for the hubs 8 to 1926. Serial No.116,222.

prevent air leakage in the openings in the heads through which the hubpasses. With downwardmovement of the pisto within the cylinder, theshaft 1 carrying the drilling tool is lowered, and with upward movementof the piston, the shaft is raised. For controlling the supply of air,and regulating the pressure ofthe air, Lhave provided a valve mechanismwhich is best illustrated in Figure 3. The casing 11a has a rocker arm12 pivotally mounted therein, and a handle 13 is extended fromt-herocker. The handle may be manually manipulated by movement in a counterand clockwise direction as illustrated. The rocker arm 12 has a roundedbearing portion 14 at one end, and a rounded bearing portion 15 at theother. The admission of air to either end of the cylinder is regulatedand controlled by a conical valve 16, which has a lower head 16aconnected therewith, which is resiliently held away from its seat 17 bya'spring 18 which is engaged at one end by a plunger rod 19. Theplungerrod 19 is movable upwardly by engagement with the rounded end 14 of therocker. Air pressure is admitted beneath the valve seat from a port 20,connected with some convenient source of air pressure. The air pressesthe head ofjthe valve seat toward shut position, so that there is acounterbalanced control which determines the seating and theunseating'of the valve" seat dependent on the proportional force exerteddownwardly by the air pressure against the head 16a and the pressure ofthe spring upwardly against the other face of the head denly, the airpressure will build up sufii ciently against the head 21c, whichw'illmove downward "as indicated exhausting through a port 21d, and thusforce the-valve16- against itsseat," Thus, Iv have provided means ofgraduallyadmitting air to the pneumatic cylinder so that variations andjerky operation isvavoided. The chamber 3 216 has at least one port 22or threaded outlet passage into which is threaded the pipe 23. The pipe23 extends to a port 24 above the piston'head in the pneumatic cylinder.Ineas-much as gradually increasing pressure for moving the shaft 1carrying the tool into the work is primarily required during thedownward movement of the drill, no provision is made for-returning thepiston head 9 under counterbalanced pressure.

For exhausting the pressure on the under side of the head, a port 25 isconnected by a pipe 25a to a cylindrical chamber 26, in which is mountedfor slidable movement a plunger 27. The plunger is pressed downwardly bya. spring 28, so that as the handle 13 is moved in a counterclockwisedirection, the port 29 into which the pipe 25a discharges is registeredwithan annular groove 30 in theplunger 27. Then theannular groove 30 isin registry with the port 29, the air is exhausted tothe atmospherethrough a port 31 extending into the cylindrical chamber.

The return stroke is accomplished by the direct introduction ofcompressed air from a pipe source such as the pipe indicated at 31a,through a port 32 into the cylindrical chamber. WVith the plunger 27 inreturn position, the port 32 registers with a groove 33 in the plunger27. In this position, a 'port 34: is also in alignment, which isconnected with a pipe 35, which extends to an orifice 36 below thepiston, so as to cause the piston to, be elevated, and thus carry theshaft 1 with the drilling tool out of thework. In the returnposition,the air from above the piston is exhausted through the pipe 37,, whichextends to the return exhaust port 38 inthe cylindrical chamber. In thereturn position, the groove 30-is aligned with both the ports 38 and'theatmospheric discharge port 31,

I so, that the air from above the piston is there by exhausted.

, "M'odifi'cationsin whichthe exposed piping will be integrally formedwith the casing walls, and in which dillerent shapes and sizes of'partsare employed, will readily occur to those skilled in the'art, withoutdeparting from the principle involved,

Having thus described my invention what I claim as new and desire tosecure by Letters Patent is:'

1. In combination with a movable member in a. machine tool, a cylinderhaving a piston V operatively connected with said member, a source ofair pressure and means for introduc-. ing therefrominto said cylinder,said means. comprising" a valve and a control handle resilientlyconnected therewith, an air passage connectedinto said cylinder, andsaidal av ng tw ads of d fie nt surface heads bein exposed to the source ofair pressure, and t e larger of said heads exposed to the pressure insaid air passage, the said heads so arranged that air pressure againstsaid smaller head will move the valve to closing position, and the airpressure against said larger head will also move said valve to closingposition, whereby the introduction ofair into the passage is regulatedby the excess of the pressure of the resilient connection over that ofthe smaller head, with the pressure of the larger head; directed-seas tocompensate for excessive introduction of air into said air passage.

2. In combination with a movable member in a machinetool, a cylinderhavinga piston operatively connected with said member, a source of' airpressure and means for introducing air therefrom into said cylinder,said means comprising a valve and a controlhandle resiliently connectedtherewith, an air passage connected into said cylinder, and

said valve having two heads of different surface area connectedtherewith, the smaller of said heads being exposed to the source of airpressure, and the larger of said heads exposed to the pressure in saidair passage,

the said heads so arranged, that air pressure against said smaller headwill movethe valve to closing position, and the air pressure againstsaid larger head will also move said. vvalve to closing position,whereby the intro- FREDERICK E. PHILLIPS.

area connected" therewith,the smaller of said i

